You can add and remove clusters and hosts from your cloud SDDC, as long as this would not bring your SDDC below the minimum or above the maximum number of allowed clusters and hosts.

The initial cluster created during SDDC creation is named Cluster-1. Additional clusters that you create are numbered sequentially, Cluster-2, Cluster-3, and so on.

When you add hosts to an SDDC with multiple clusters, you can select the cluster to add them to.